The Investigators: Quadruple Murder

It was one of the worst homicides in Los Angeles County in five years. In July, in one house, four people from one family were murdered, including an eight-year-old girl who was tortured and sexually assaulted.

Crime scene investigators with the LA Sheriff's Department crime lab were soon on the scene. Sergeant Larry Mitchell lead the investigation. 48 Hours Investigates was on the scene with him as he worked. Richard Schlesinger reports.

With young grandchildren of his own, Mitchell, 56, might well have a hard time keeping this from getting personal. But 19 years of working crime scenes has taught him to forget his emotions and rely on his instincts.

He begins by looking for anything unusual at the crime scene: "You're pretty much looking for anything that you see that's out of place," he says. "Things that are out of place, that maybe someone grabbed. Maybe someone touched, to give you a fingerprint. Or maybe give you some DNA that can lead you to a suspect."

But even Mitchell finds it tough to stay focused on the job at hand when he gets his first look inside the Ruiz house. "I haven't seen very many crime scenes as violent as this one. There's a lot of violence here," he said.

Sometime between Friday and Saturday morning, in a Los Angeles suburb, 38-year-old Miguel Ruiz, his wife Maritza Trejo, his grandmother Ana Luisa Martinez, and his 8-year-old daughter Jasmin Ruiz were murdered.

"They pretty much ransacked the house," Mitchell said. "We got blood everywhere, on the walls, on the floor. It looks a though they tried to clean the place up a little bit cause there is a mop and bucket there. Lot of work to do."

"It doesn't appear someone broke into the house. It was almost like they were let into the house," he added.

"That was my baby, Jasmin. She had 1,001 friends, the center of attention at all times wherever she went," said Olga Ruiz, who lost most of her family that morning, including her brother Miguel. "They were a great family, a working class family." Miguel was a stay-at-home father who had a small business building computers.

According to police, almost all criminals make mistakes and leave evidence behind and the crime lab is where they get caught.

The L.A. County crime lab is one of the best equipped in the country, and with good reason. They investigate over 70,000 cases each year.

The crime lab will pull out all the stops on this one, photographing every piece of evidence, analyzing blood and fluids, examining the tiniest bits of evidence: DNA testing, fingerprint processing and identification.

For hours on Saturday, the investigators comb every inch of the house. It is a painstakingly slow and meticulous process, a long day and an even longer night.

"In the real world, this is a very stressful job," says Mitchell. "You're dealing with a lot of trauma. You're dealing with innocent people who have been brutally murdered. You deal with the pressure of knowing that you only have one chance to process this scene and once you're done, you can't go back."

At 11:30 pm on Saturday, 12 hours after the investigation began, the bodies of the Ruiz family are finally removed from the house. On Sunday Mitchell and his team were back at work. But they haven't made a dent in the mountain of evidence left behind by the killer of the Ruiz family.

"Unlike the CSI show, where we see everything is pretty much done in an hour's worth of view time, that's not the way it is in reality," says Mitchell. "We come back for as often or as long as we have to to get it right. Because one thing about a crime scene, you only have one time to get it right."

The Ruiz house looks like something out of a horror movie. But a closer inspection reveals what appears to blood on the walls is, in fact, something else entirely: pancake syrup, Italian dressing, barbeque sauce, all kinds of food products.

Mitchell thinks whoever did covered the walls was trying to trick investigators somehow.

The investigators work in teams. The identification team gathers fingerprint evidence and documents the scene. The biology team analyzes and interprets blood evidence.

Thirty hours into the investigation, one detail catches the eye of an investigator: a chair out of place. Investigators think the chair was moved from the dining room into the bedroom.

Did the killer move the chair? If so, did he leave some trace behind? Using a gadget called an electrostatic dust lifter, they find shoe prints.

"See all the nicks and gouges?" says one of the investigators. "That shoe, if we find it, we can make a conclusive match with those marks."

With photos of the shoeprints in hand, detective Ray Peavy sends his homicide detectives to canvass the neighborhood.

In a house just around the corner, they find a suspect wearing a pair of shoes with soles similar to the prints lifted from the chair. They asked him if they could look at his shoes. The suspect agrees, and the shoes are taken to the lab.

Bob Keil is, among other things, an expert, in shoeprints. After examining them, he is sure they match. "There is no doubt in my mind that these prints came from this pair of shoes to the exclusion of all other shoes in the world."

That was good enough for detectives. Less than 48 hours after the murders they arrested 23 year-old Alfonso Morales.

"It did make the hair stand on the back of my neck," says Keil. "I knew at that point, because of the gravity of the crime - a child was murdered - basically, a whole family was wiped out, that I'm going to have a hand in this. And this person is going to have an answer."

Morales not only lived nearby, he occasionally helped Miguel Ruiz with his computer business. Investigators think the two men had a falling out when Morales was told to stay away from Ruiz's daughters.

When the crime scene investigators searched Morales' house they turned up even more evidence: a large garbage can filled with items stolen from the crime scene, as well as a t-shirt possibly stained with blood.

Morales pled not guilty at his arraignment and he's in jail waiting for his trial. He could face the death penalty.

Even as the investigators worked the Ruiz case, other work was already piling up. "From Thursday afternoon we had 17 homicides. Even for us, that's quite a run in such a short amount of time," says Mitchell.

Although tired, he and his team are ready: "Everybody in this unit is here because they want to be here and this is what they want to do." "They love the challenge of getting calls, working these difficult scenes. They love the opportunity to put their skills to work. And we're fine. We're ready for the next one."